The final process of surface treatment by roller or ball imprinting brings many benefits. The workpiece surface becomes smoother and hardened than with turning or grinding. The following are tools for rolling and processing with a diamond ball from the manufacturer Cogsdill.
Rolling is the final surface treatment process in which hardened and polished steel rollers are impressed into the softer surface of the workpiece. The pressure created by the rollers is greater than the material's yield strength of the workpiece, so the surface undergoes cold plastic deformation. The obtained workpiece surface is shiny smooth and has a hardened surface layer. It also has better load-bearing properties, so its mechanical properties are generally better than those obtained by cutting or grinding.
The cutting or grinding process on the workpiece surface cuts or tears metal and creates a structure of sharp peaks and valleys. In the imprinting process, these micro-peaks are plastically deformed and flow into the valleys, resulting in a flattened surface profile with no sharp peaks. Because the surface layer is hardened during imprinting, such a surface in contact with another machine part will have longer durability.
So, rolling with rollers yields three main benefits:
1. Accuracy of the workpiece dimension - with rolling tools, any piece made by cutting can be quickly processed. Rolling with rollers can be done on both conventional machines and CNC machining centers.
2. The rolling tool also has a stepwise diameter adjustment of 2.5 microns or 5 microns - depending on the size of the rolling tool. The final workpiece dimension is achieved by a simple manual adjustment of the rolling tool. The set dimension remains stable throughout the rolling process.
3. Improved surface treatment - when rolling, we do not use cutting or abrasion but compress micro-peaks on the surface into valleys. This results in a dense and uniform surface with a lower friction coefficient. The process takes only a few seconds, significantly less than grinding, drilling, or honing, which take several minutes.
4. Hardened surface - using rolling as the final processing step, we can quickly harden and align the surface to size. Surface hardness increases from 5% to 10%. The hardened layer extends to a depth of 0.254 mm to 0.762 mm. A smooth and hardened surface significantly extends the wear resistance of machine parts and corrosion resistance.
Depending on the type of processing, we can choose between tools for rolling internal or external surfaces. For internal surface processing, the SRM tool is intended, with versions for through-hole processing (SRMR) or blind hole processing (SRMB), with tool diameters from Ø4 mm to Ø114 mm. For external diameter processing, the XBB tool is available with tool diameters from Ø1.5 mm to Ø65 mm. These mentioned tools are readily available from the European warehouse.